The proposed investigation is designed to yield structural and functional information about the regulation of gene expression in the bacteriophage T7 as well as in eukaryotic organisms. Description of protein-nucleic acid interactions will be obtained by analyzing (1) T7 RNA polymerase-promoter interactions and (2) small ribonucleoprotein particles whose RNA components are tRNAs. Elucidation of the function of these tRNA-RNPs will be sought.